In a known mobile speaker system, the system is separately attached to the vehicle tray for both the left and right channels by mounting or embedding means, although there are different types of mobile speaker systems, (e.g., three-way systems multi-way systems, and the like). In the case of a fixed-type system, the left and right speaker systems are independently or separately fixed on the tray of the vehicle.
Accordingly, although the design of a vehicle may change each year, there is little freedom to change the design of the speaker system from the connection with the vehicle. The shape of the cabinet cannot be largely changed due the limitation or requirement of mobility. Accordingly, the design lacks novelty. Further, it is difficult to find the best design of the vehicle space, which can be tightly closed, relative to ideal acoustical conditions. In particular, although it is desirable to use a bass-reflex type speaker cabinet, rather than an air-tight speaker cabinet, to expand a flat reproducing band, there is a problem in that the duct opening cannot be made sufficiently large.